In this case [the testifying psychiatrist] ... proposed the following criteria by way of particularisation:

For capacity to consent to sex to be present the following factors must be understood:

1. The mechanics of the act

2. That only adults over the age of 16 should do it (and therefore participants need to be able to distinguish accurately between adults and children)

3. That both (or all) parties to the act need to consent to it

4. That there are health risks involved, particularly the acquisition of sexually transmitted and sexually transmissible infections

5. That sex between a man and a woman may result in the woman becoming pregnant

6. That sex is part of having relationships with people and may have emotional consequences

The next question is to decide whether the six criteria of Dr Hall do indeed accurately particularise the simple test of Munby J. It is fair to say that neither counsel supports the inclusion of the sixth criterion as an essential ingredient of capacity to consent to sex (viz "an awareness that sex is part of having relationships with people and may have emotional consequences"). I agree. This criterion is much too sophisticated to be included in the low level of understanding and intelligence needed to be able to consent to sex. Apart from anything else, I would have thought that a deal of sex takes place where one or other party is wholly oblivious to this supposed necessity.

Counsel are agreed that an awareness and understanding of the first, fourth and fifth criteria are indeed essential ingredients of the capacity to consent to sex. They are divided as to the inclusion of the second (age) and third (consent). Mr O'Brien strongly argues that the law requires their inclusion; Mr Sachdeva states that "they go beyond the factors which have been expressly stated as being necessary elements of capacity to consent to sex in previous case law".

So the question that I have to answer is this: in order to be able to consent to sex does a person need to have a proper and full(ish) awareness and understanding that sex should only be done by people over 16, and that it should be consensual? It is not an answer to the question to observe that sex with minors, and non-consensual sex, are horrible perversions. There are plenty of paedophiles out there who through warped ideology actually believe that it is morally acceptable to have sex with children. Equally, the prisons have numerous rapists within their walls. But paedophiles and rapists have the capacity to consent to sex.

Mr O'Brien says that this argument is over-intellectual. We are dealing here, he says, with mentally incapacitated people, who in the terms of s2(1) of the Act are suffering impairment of, or a disturbance in the functioning of, the mind or brain. We are not talking about perverts who obviously have the capacity to consent to sex. This is true enough, but I believe that to import these knowledge requirements into the capacity test elevates it to a level considerably above the very simple and low level test propounded by Munby J namely "sufficient rudimentary knowledge of what the act comprises and of its sexual character".

In his evidence Dr Hall emphasised that the need for consent is one of the very first messages that is conveyed to people with learning disabilities who are being taught about sex. Nothing I say is intended to diminish that obviously vital message. There is a difference, however, between the teaching of what is right and wrong in the pursuit of sex, and what level of understanding and intelligence is needed to be capable of consenting to it.

I therefore conclude that the capacity to consent to sex remains act-specific and requires an understanding and awareness of:

The mechanics of the act

That there are health risks involved, particularly the acquisition of sexually transmitted and sexually transmissible infections

That sex between a man and a woman may result in the woman becoming pregnant

After considering "Alan"'s knowledge of various sexual acts and related issues, the judge elected to enter only a temporary order stating that the subject lacked capacity to consent, with the caveat that "the local authority [] provide Alan with sex education in the hope that he thereby gains that capacity."

Incidentally, I passionately hate reading English legal opinions due to the formatting and citation conventions, but the decision to number paragraphs is a very elegant way to circumvent dependence on pay sites for pagination information. Is there some reason why this could not be adopted by judges in the United States?

In this case [the testifying psychiatrist] ... proposed the following criteria by way of particularisation:

For capacity to consent to sex to be present the following factors must be understood:

1. The mechanics of the act

2. That only adults over the age of 16 should do it (and therefore participants need to be able to distinguish accurately between adults and children)

3. That both (or all) parties to the act need to consent to it

4. That there are health risks involved, particularly the acquisition of sexually transmitted and sexually transmissible infections

5. That sex between a man and a woman may result in the woman becoming pregnant

6. That sex is part of having relationships with people and may have emotional consequences

The next question is to decide whether the six criteria of Dr Hall do indeed accurately particularise the simple test of Munby J. It is fair to say that neither counsel supports the inclusion of the sixth criterion as an essential ingredient of capacity to consent to sex (viz "an awareness that sex is part of having relationships with people and may have emotional consequences"). I agree. This criterion is much too sophisticated to be included in the low level of understanding and intelligence needed to be able to consent to sex. Apart from anything else, I would have thought that a deal of sex takes place where one or other party is wholly oblivious to this supposed necessity.

Counsel are agreed that an awareness and understanding of the first, fourth and fifth criteria are indeed essential ingredients of the capacity to consent to sex. They are divided as to the inclusion of the second (age) and third (consent). Mr O'Brien strongly argues that the law requires their inclusion; Mr Sachdeva states that "they go beyond the factors which have been expressly stated as being necessary elements of capacity to consent to sex in previous case law".

So the question that I have to answer is this: in order to be able to consent to sex does a person need to have a proper and full(ish) awareness and understanding that sex should only be done by people over 16, and that it should be consensual? It is not an answer to the question to observe that sex with minors, and non-consensual sex, are horrible perversions. There are plenty of paedophiles out there who through warped ideology actually believe that it is morally acceptable to have sex with children. Equally, the prisons have numerous rapists within their walls. But paedophiles and rapists have the capacity to consent to sex.

Mr O'Brien says that this argument is over-intellectual. We are dealing here, he says, with mentally incapacitated people, who in the terms of s2(1) of the Act are suffering impairment of, or a disturbance in the functioning of, the mind or brain. We are not talking about perverts who obviously have the capacity to consent to sex. This is true enough, but I believe that to import these knowledge requirements into the capacity test elevates it to a level considerably above the very simple and low level test propounded by Munby J namely "sufficient rudimentary knowledge of what the act comprises and of its sexual character".

In his evidence Dr Hall emphasised that the need for consent is one of the very first messages that is conveyed to people with learning disabilities who are being taught about sex. Nothing I say is intended to diminish that obviously vital message. There is a difference, however, between the teaching of what is right and wrong in the pursuit of sex, and what level of understanding and intelligence is needed to be capable of consenting to it.

I therefore conclude that the capacity to consent to sex remains act-specific and requires an understanding and awareness of:

The mechanics of the act

That there are health risks involved, particularly the acquisition of sexually transmitted and sexually transmissible infections

That sex between a man and a woman may result in the woman becoming pregnant

After considering "Alan"'s knowledge of various sexual acts and related issues, the judge elected to enter only a temporary order stating that the subject lacked capacity to consent, with the caveat that "the local authority [] provide Alan with sex education in the hope that he thereby gains that capacity."

Incidentally, I passionately hate reading English legal opinions due to the formatting and citation conventions, but the decision to number paragraphs is a very elegant way to circumvent dependence on pay sites for pagination information. Is there some reason why this could not be adopted by judges in the United States?